The Santa Cruz, Calif.-based company says it made upgrades on the inside and outside, including "complete overhauls" of its Zero S and Zero DS models. The new bikes charge in four hours standard and 2.3 hours in "quick-charge" mode.

But the big selling point here is that the bikes are now compatible with J1772 public charging stations via an optional accessory, allowing them to leverage a growing network of charge stations.

Zero says it increased the capacity of the bikes' lithium-ion power packs by 12.5 percent to boost range -- you're looking at roughly 60 miles per charge -- as well as implemented more precise charge indicators, along with a rash of more conventional upgrades, from suspension to brakes to body.

"During the past year, our engineering and manufacturing teams have benefitted from experienced new leadership and the results are clear," CEO Gene Banman said in a statement. "In close coordination, they have been working overtime to design and build the world's finest collection of electric motorcycles."

The new models -- Zero S, Zero DS, Zero MX and Zero X -- are available now for $9,995; $10,495; $9,495; and $7,995, respectively. Federal tax credits up to 10 percent of MSRP are available for the bikes.

Here's a video on how former California governor Arnold Schwarzenegger feels about them: